Typewriting machines – Sheet or web – Including programmed-control-system for record-medium feed
Reexamination Certificate
1999-04-13
2002-10-29
Hirshfeld, Andrew H. (Department: 2854)
Typewriting machines
Sheet or web
Including programmed-control-system for record-medium feed
C400S578000
Reexamination Certificate
active
06471428
ABSTRACT:
This application is based on Patent Application Nos. 121832/1998 and 121833/1998 both filed on Apr. 15, 1998 in Japan and the content of which is incorporated hereinto by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a feeding apparatus and a printing apparatus which can be coupled with each other, and a feeding control method. More particularly, the invention relates to a feeding apparatus and a feeding control method for feeding a printing medium, such as a paper or the like, to a printing apparatus, and a printing apparatus for printing information, such as a document, graphic image and so on processed by an information processing system, on a printing medium, such as a paper or the like.
In the present invention, a feeding apparatus and a feeding control method perform feeding of a printing medium automatically in accordance with a command from a printing apparatus to which the feeding apparatus is connected. Therefore, they are also called an automatic feeding apparatus and an automatic feeding control method.
2. Description of the Related Art
Demand in the market for downsizing and weight lightening for a printer as a printing apparatus has been growing similarly to other various devices. For satisfying such demand, downsizing and weight lightening in the printer have progressed significantly. Seeking downsizing of the printer, there has been proposed a printer, in which a main body portion of the printer performing image printing and an automatic sheet feeder (hereinafter referred to as “ASF”) portion for feeding a plurality of stacked sheets as printing media to an image forming portion one by one are separated, as disclosed in Japanese Patent Application Laid-open No. 4-303336 (1992). Namely, the ASF portion is made independent of the main body of the printer for external attachment. On the other hand, not only in the small size printer, but also in a printer having a plurality of paper feeding openings or a printer permitting only manual paper feeding, there has been conventionally known of ASFs which can be externally installed. It should be noted that various media in addition to paper are included as the printing media.
In the ASF disclosed in Japanese Patent Application Laid-open No. 4-303336, namely, in the ASF to be externally installed on the printer, a drive system of a feeding roller feeding a sheet one by one is constructed. The drive system is constructed by coupling driving power transmission means, such as a gear exposed outside of the ASF, and driving power transmission means exposed outside of a printer body. And, a driving force, such as a motor within the printer body, is used as the driving force of the feeding roller. In such driving method, since it becomes unnecessary to independently provide a driving source, such as a motor or the like and an electric source on the side of the ASF, the ASF can be constructed at low cost and light weight. However, on the other hand, for limitation of freedom of mechanical components arrangement in the ASF, it is not always possible to set optimal position for the ASF for downsizing and stability of performance.
On the other hand, for example, as disclosed in Japanese Patent Application Laid-open No. 9-194085 (1997), there has been proposed the ASF incorporating a motor as a driving source of the feeder roller for external installation. In this case, freedom of the mechanical components arrangement is increased to permit arrangement of the parts of the paper feeding mechanism independent of the construction of the printer body. Upon making the ASF perform paper feeding operation, through electrical contacts provided on a mating portion between the printer body and the ASF, a controller provided within the printer body applies an electrical signal to the motor for driving the paper feeder roller for driving the latter.
However, a sheet, on which an image is printed by the printer, is not limited to a plain paper, but can be of wide variety of size and thickness, such as a postcard, cardboard, envelope and so on. On the other hand, due to progress of printing technology in printers, such as that of an inkjet type and so on, more fine ink droplet or high and low density ink droplets can be ejected to permit formation of a high quality image with higher definition and superior tone reproducibility. For making high image quality effective depending upon purpose, special sheets, such as a coated paper, a glossy paper, a glossy film, an OHP film, a cloth, an iron transfer paper and so on have been developed.
In the ASF which can be installed in the printer, there has been required a performance for certainly feeding various kinds of sheets without causing any problem. However, the sheets as the printing medium should differentiate optical feeding conditions depending upon thickness, sizes or surface characteristics thereof.
Since the conventional ASF, which can be installed on the printer as set forth above, has no feeding operation control means for driving the feeding roller by driving the motor, control of the paper feeding operation by the ASF is performed by the printer. Therefore, control means within the printer is required to have feeding operation control function having feeding conditions adapted to various sheets. Therefore, in addition to control for the printer body, the necessity set forth above makes control software large and complicated.
On the other hand, in some printer bodies, it is required to use an external ASF dedicated for postcard feeding, an external ASF for continuous sheet feeding and so on in addition to the normal external ASF, or to use a new type and improved type of external ASF. If feeding operation control of the ASF is different even in part, the printer body has to have control functions for all of the feeding operation. Therefore, software in the printer body becomes further complicated, or in worse case, modification of the software becomes necessary, and a problem in compatibility is possibly caused. On the other hand, a large number of printer bodies are in the market so that modification of the software on the side of the printer body is substantially impossible. In the alternative, upon providing a new external ASF, it is required that paper feeding can be performed without causing any problem by the existing control function for the feeding operation which has been provided in the printer. Therefore, designing freedom of ASF is restricted significantly.
On the other hand, the ASF, such as that disclosed in Japanese Patent Application Laid-open No. 4-303336, is generally constructed with a pressure plate, on which sheets are stacked, a paper feeding roller for feeding sheets as the printing media stacked on the pressure plate one by one, a paper transporting roller and a pinch roller for pinching and transporting the sheets fed from the feeding roller. As the printing medium, in addition to paper, various other media should be included. In the sheet feeding operation, at first, the feeding roller on the upstream side in a transporting direction is driven for rotation, so that the sheet is fed. Thus the tip end of the sheet abuts with a nip portion formed by the transporting roller and the pinch roller on the downstream side in the transporting direction. Subsequently, the sheet is forced into the nip portion by further rotating the feeding roller to perform registration. Thereafter, by driving the transporting roller, the sheet is transported to be fed into a printing portion of the printing apparatus.
On the other hand, in so-called positioning top of sheet, by rotation of the transporting roller, the transporting roller grips the tip end portion of the sheet abutted to the nip portion. Upon such positioning top of sheet, when the feeding roller is in pressure contact with the rear end portion of the sheet, significant back tension should be exerted on the sheet on the downstream side in the transporting direction, so that precision of positioning top of the sheet is degraded. In order to prevent this, an arc-shaped roller
Asano Shinya
Hasegawa Koh
Inoue Hiroyuki
Iwasaki Takeshi
Kawasaki Noriko
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Hirshfeld Andrew H.
Nolan, Jr. Charles H.
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